Selective attention is a cognitive ability that enables the processing of relevant stimuli while minimizing interference from irrelevant and/or distracting events. An overall goal of the research proposed here is to elucidate the neural mechanisms of attentional processes in order to test specific models of voluntary attention and provide basic science information relevant to the diagnosis and treatment of disorders that include deficits of attention. In conjunction with psychophysical measures, event-related potentials (ERPs) and oscillatory activity in the electroencephalogram (EEG) will provide high temporal resolution measures of neural activity supporting attentional control and stimulus selection. Functional magnetic resonance imaging (fMRI) will be employed to identify the neuroanatomical systems and networks involved in attentional control and selection. This application has three specific aims: (1) Determine how changes in background neural activity in visual cortex during preparatory attention influence selective sensory processing and performance;(2) Determine the role of preparatory attention in establishing the locus of attentional selection during ascending sensory processing;and (3) Determine the mechanisms of target facilitation and distractor inhibition processes in attentional selection. Throughout the proposed research, the combined use of EEG/ERPs and fMRI will provide complementary measures of the time course and functional anatomy of attentional mechanisms.